The breast is a specialized, glandular structure including a system of complicated breast ducts that radiate from the nipple and that are bound together by fairly dense connective tissue. Each of these breast ducts includes an associated ductal orifice on the surface of a nipple through which ductal fluid may be expressed. Each duct includes a series of successive interlobular branches that drain through the main, lactiferous branch, which terminates and exits the breast at the nipple via the associated ductal orifice. Immediately proximate the ductal orifice, each lactiferous duct includes a lactiferous sinus in which ductal fluid may accumulate. A ductal sphincter resides within the lactiferous sinus and prevents ductal fluid from unintentionally exiting the breast duct through its associated ductal orifice.
Breast cancer is believed to begin in the lining of these breast ducts. For several decades significant members of the medical community dedicated to studying breast cancer have believed and shown that the cytological analysis of cells retrieved from nipple discharge fluid from within breast ducts may provide valuable information leading to identifying patients at risk for breast cancer. Indeed, Papanicolaou contributed to the genesis of such a possibility of a “Pap” smear for breast cancer by analyzing the cells contained in nipple discharge. More recently, cancer specific markers have been detected in ductal fluid obtained by nipple aspiration. However, the retrieval techniques and instruments used by these members of the medical community did not routinely obtain meaningful ductal fluid samples.
In their attempts to retrieve the breast duct fluid sample including ductal epithelial cells, practitioners introduced wash fluids into a breast duct using indwelling hair-like single lumen catheters. After the fluid was introduced into the duct, the fluid introduction catheters were removed. Then, externally applied nipple aspiration techniques or external pressure applied to the breast were used to collect samples of the ductal fluid. However, these techniques required that significant, sometimes painful, pressure be created on the nipple surface or along the sides of the breast to overcome the fluid retaining properties of the ductal sphincter. Also, these techniques did not routinely provide meaningful ductal fluid samples with a sufficient number of ductal epithelial cells for a meaningful cellular analysis. These techniques typically caused the recovery of samples with twenty or fewer ductal epithelial cells.
Additionally, these techniques did not provide samples with cell clusters of 10 or more cells. As a result, the obtained fluid samples could not consistently provide an accurate indication of whether or not the duct from which they were retrieved included precancerous or cancerous cells. Consistent, meaningful ductal epithelial cell samples have been provided by the medical instrument disclosed in U.S. Pat. No. 6,413,228 to Hung et al. that is hereby incorporated by reference in its entirety.
The human breasts are composed of fatty tissue, fibrous tissue, breast ducts and milk glands. Human breasts are believed to contain from 6 to 8, or more breast ducts. The ductal lavage procedure discussed above, and sampling results may be greatly effective in screening patients for an early warning of breast cancer risk. However, in performing the ductal lavage procedure, a physician may have difficulty inserting the catheter into a breast duct. The breast duct is a complex anatomical pathway to the breast milk glands. The physician must access the breast duct so as not to cause damage to the inner walls of the duct and/or avoid puncturing the duct. However, it is believed the deeper a catheter is inserted into breast duct, the greater the risk of puncturing the breast duct walls. Therefore, a need exists for a ductal access catheter that allows the physician to adjust its flexibility and rigidity so as to adapt the catheter to the ductal geometry and direct the catheter deep into branches of the ductal network.
During the ductal access procedure, a catheter is inserted into a duct opening in the nipple that may cause some discomfort to the patient. Thus, improved insertions systems and methods for ductal access are needed.